cmis170fandomcom-20200214-history
CMIS170 Wiki
Welcome to the CMIS170 Wiki XML and Databases - Final Project for XML Course Authors: Acevedo, Dunn, Peet Describe your topic Write a description about your topic. Let your readers know what your topic is about and add some general information about it. XML and Databases The application of the Extensive Markup Language in conjunction with databases is a topic that is further discuss. An alternate way of extracting and storing data shows the relation between XML technologies and databases features. To better understand these two entities let us dissect and explain databases and XML. Database in computer information technology is a compilation of information, or stored data that is later retrieve. (Richardson, 2015) Divides databases into five categories of features. These are: · Data Model – Relational model, Key Value Model, Hierarchical model · Application Programming Interface (API) – In process vs. Out of process; SQL vs. NoSQL · Transaction – Atomicity, Consistency, Isolation, Durability · Persistent – Row-based, Column-based, Memory only, Distributed · Indexing – B- tree, B+ tree Everyone who is in the computer information technology field have experienced databases at one time in their studies or career. However, databases are not limited only to the computer science field. Extensive Markup Language or XML derived from Standard Generalized Markup Language (ISO 8870:1986). XML allows data processing with relatively little human interaction due to its textual format. XML has remarkably taken off, and its used is very common in sharing information across networks and applications. XML has prominently succeeded in the application such as podcasting, data storage, and Web services. A XQuery permits the access of information from databases. This XML technology is a language that queries data whether “physically stored in XML or viewed as XML via middleware” (W3C, 2010). XQuery is to XML what database tables are to SQL. XQuery ideally queries XML documents or a mixture of XML and relational sources where SQL retrieves data from relational databases (Jackson, 2005). Data Storage Not so many years ago, one could store data in an efficient tabular form (relational databases such as Oracle or SQL) or in XML which more easily handles nested data and text documents. Fortunately, we now have hybrids of these two systems which gives us the advantages of both systems. Extracting Data from XML – The Data Models *XML is a text based language. Once XML is read into memory, however, it is typically represented as a tree. There are numerous ways to represent and access these trees which are all very similar, but which have differences, including diverse limitations and advantages. Three of the primary models include document object model (DOM), XPath Data Model (XDM), and Post-Validation Information Set (PSVI). *DOM forms the basis of many other powerful implementations. Each item in an XML document (element, attribute, blocks of text, etc) is represented as a node with dependent items drawn as child nodes. There are different types of nodes (element node, attribute node, etc.) which have different properties. When accessed, the low level DOM application programming interface (API) returns a node list. DOM does have its limitations though. For one, it is quite verbose when compared to other applications. The XML Path Language (XPath), while not a standalone language in its own right, is designed to be embedded in and used by multiple other languages such as XSLT, XLink, XPointer, and XQuery. It can be used from PHP, Python, C, C++, Java, and a host of other languages. Early XPath (XPath 1.0 which is still widely used) utilizes DOM APIs to return a node list. It is an easy and intuitive method for finding items in XML trees. It is the basis for XSLT and XQuery Latest activity Photos and videos are a great way to add visuals to your wiki. Find videos about your topic by exploring Wikia's Video Library. Category:Browse